Electrode wire feeding means for welding apparatus

ABSTRACT

Electrode wire-feeding means for electric arc-welding apparatus in which the electrode wire is conducted through a flexible conduit from a remote wire source to a manually operable welding gun at the point of use, first wire feed rollers at the gun being driven by an air motor controlled at the gun to regulate the rate of wire feed and pull the wire through the flexible conduit, second wire feed rollers being provided at the wire source driven by an electric motor, known in the industry as a &#39;&#39;&#39;&#39;torque motor, &#39;&#39;&#39;&#39; for applying a propelling force to the wire, such force having a maximum limit as determined by the maximum stalled output torque of the motor, this motor having an energizing circuit controlled by a switch at the gun, and including selective switch controlled means operable at the remote station for changing the value of the maximum stalled output torque of the electric motor depending upon whether a relatively large or small sized wire is being used.

United States Patent [72] Inventor MiloM.Kensrue Santa Ana, Calif. [21Appl No. 744,006 [221 Filed July 11.1968 [45 Patented Feb. 9, 1971 [73]Assignee M.K. Products, Inc.

a corporation of California [54] ELECTRODE WIRE FEEDING MEANS FORPrimary ExaminerBernard A. Gilheany Assistant ExaminerRoy N. Envall, Jr.Attorney-Wham & McManigal ABSTRACT: Electrode wire-feeding means forelectric arcwelding apparatus in which the electrode wire is conductedthrough a flexible conduit from a remote wire source to a manuallyoperable welding gun at the point of use, first wire feed rollers at thegun being driven by an air motor controlled at the gun to regulate therate of wire feed and pull the wire through the flexible conduit, secondwire feed rollers being provided at the wire source driven by anelectric motor, known in the industry as a torque motor, for applying apropelling force to the wire, such force having a maximum limit asdetermined by the maximum stalled output torque of the motor, this motorhaving an energizing circuit controlled by a switch at the gun, andincluding selective switch controlled means operable at the remotestation for changing the value of the maximum stalled output torque ofthe electric motor depending upon whether a relatively large or smallsized wire is being used.

Z2 7 b Z./@/ 6 7 ELECTRODE WIRE FEEDING MEANS FOR WELDING APPARATUSBACKGROUND OF THE INVENTION The present invention relates generally tothe electric welding art.

The present invention constitutes an improvement in welding apparatussuch. as that shown in my U.S. Pat. No.

3,305,664 which was granted on Feb. 21 1967, and wherein an electrodewelding wire is pulled to a welding gun at the work location and underthe control of the welder, by means of a feed mechanism. The wire issupplied to the gun through a flexible conduit from a remote wiresource. 7

The use of a single-pull type of feed presents well-known problems, andin order to improve this type of feed and provide increased flexibilityof operation, it has heretofore been suggested to supplement the pullfeed mechanism at the gun with a push type feed at the wire source whichwould be arranged to constantly apply a driving torque force.Supplemental feeds of this character were inthe main designed to beactuated by power means such as a torque motor having a predeterminedmaximumdriving torque. The usual practice has been to utilize a motor ofthis character in which the amount of torque was dictated by the maximumsize of the wire to be used. Under s'uchcircumstances, satisfactory feedcould be obtained with the larger wire sizes, but problems developedwhen the same torqueor pushing force capabilities were applied to thesmaller wire sizes.

For example, it has been found that in the case of relatively smalldiameters of aluminum welding wire, flller wire and the like of theorder of .030 inches to .035. inches, a reduction of the wire feed rateat the gun tended to cause a kinking or bowing condition of thesmallwire within the flexible cable in such a way as to impede its forwardmovement, and in resumption of an increased feeding rate at the gun thekinked wire would produce undesirable feed regulations to appear. On theother hand, if the driving torque force which was to be applied at thesource was chosen so as to be proper for the smaller diameter wires,then there was invariably an insufficiency of 'driving force forthewires'of the larger diameters .under 'certain conditions, and thewire friction could under such circumstances provide undesirable anderratic feeding action. 1

It is therefore proposed in the presentinvention to provideversatile'power means wherein by a simple procedure, for example,by'simply changing a control switch from one position to another, changethe torque outputcharacteristics of the feed mechanism at the source toeither a high" torque or low torque mechanism, depending upon whether itis desired to'feed a heavy or light welding wire.

SUMMARY OF THE INVENTION The present invention relates generally toelectric arc-welding apparatus, and is more particularly concerned withimprovements in the mechanism for feeding of an electrode wire from aremote source through a flexible conduit to the point of use.

It isone object of the present invention toprovide in welding apparatus,improved electrode wire-feeding means in whichlhe wire is pulled to awelding gun through a flexible casing or a conduit from a remotewire-source, and at the same time is pushed at the wire source end ofthe conduit by a continuously applied predetermined force.

A further object is to provide wire-feeding means according to theforegoing object, wherein theapplied predetermined force is generated bypower means having a selectable maximumstalled driving torque output.

Another object resides in the provision of a wire feed mechanism for awelding gunwhich includes a wire-moving mechanism at the wire source forpushing the wire through a flexible conduit to the gun, the mechanismbeing power driven by an electric torque motor" having predeterminedmaximuni torque output selectable to'operate at a relative high torqueand at a relatively low torque.-

Still another object is to provide in a wire-feeding mechanism, a uniquedrive including a torque motor of the split field type having acapacitor in circuit with one of its field portions operable to providea high-torque output for feeding relatively large wire, and a resistorconnectable in circuit with the capacitor to provide a low-torque outputfor feeding relatively small wire.

It is also an object to provide a wire-feeding mechanism for weldingapparatus, in which a controlled variable wire feed at the welding gunis operated in combination with a feed mechanism at the wire source, thelatter having selectable maximum stalled output torque characteristicsdepending upon whether a heavy wire or fine wire is being used, andwhich may be changed to the low-torque delivery in order to preventkinking of the small wire during feeding operations.

Further objects of the invention will be brought out in the followingpart of the specification, wherein detailed description is for thepurpose of fully disclosing the invention without placing limitationsthereon.

BRIEF DESCRIPTION OF THE DRAWINGS Referring to the accompanyingdrawings, which are for illustrative purposes only:

FIG. 1 is a side elevational view of a welding gun having a pull-typewire-feeding mechanism, the gun being associated with a source push-typefeeding unit as diagrammatically illustrated, and embodying the featuresof the present invention; and

FIG. 2 is an enlarged fragmentary detail view of the feeding mechanism,including a schematic representation of the motor control torquechanging circuitry.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Forillustrative purposes, there is shown in FIG. 1 a welding gun or torch Thaving a construction corresponding generally to the torch shown in myissued U.S. Pat. No. 3,305,664. In the present instance, detailsare'shown with respect to only those parts which are concerned directlywith the present inventlon. i

, In general, the torch comprises an elongate housing 10 of generallytubular construction, this housing at one end having a straight bodyportion 11 which forms a handgrip and is continued into a neck extension12 at the opposite end having a curved axis. The outermost end of thisneck is connected with a welding nozzle 13 through which an electrodewire W is fed into the weld which is being made on a workpiece 14. Asuitable inert gas is supplied to the weld through a conduit 15 havingone end appropriately connected with the nozzle 13 and its other endconnected with a suitable connection fitting l6 by means of whichconnection may be made to a suitable source of supply through aconventional conduit (not shown).

The electrode wire W is fed to the weld through a wire guiding tubecomposed of cooperative sections and 17b, having their innermost ends inaxially aligned spaced end-to-end relation. The first section 17aconnects with the nozzle 13, while the other section 17b terminates in aconnection fitting 18 adapted for connection with one end of a flexibleconduit or casing 19 leading to a remotely located wire-feeding unit 20at the wire source of supply.

At the torch, the electrode weldingwire W is led into the tube section l7b from the connection fitting 18 and thence through the section 17a.This wire is fed by means of cooperatively associated rollers whichconsist of a drive roller 21 and an idler roller 22 which are positionedin a gap or space 23 between the ends of the tube sections 17a and 17b,the welding wire W passing between these rollers. The rollers may haveserrated peripheries so as to better engage the wire, the drive roller21 being power driven through a connecting shaft 24. The idler roller 22may be provided with suitable adjusting means (not shown) by which itspressure engagement with the wire may be varied.

The shaft 24 of the power driven roller is connected with a speedreduction device 25 which is connected at one end of a driving motorhousing 26. This motor is of a type which is arranged for operation byfluid under pressure, such as air or other gas, and has an axis ofrotation which is positioned in parallel relation to the longitudinalaxis of the handgrip portion 11 of the housing. This motor has an endcap 27 to which there is secured an inlet conduit 28 for themotor-actuating fluid, the outermost end of this conduit terminating ina connection fitting 29 which serves both as a connector for supplyingfluid to the motor as well as electric power to the welding wireelectrode as it passes through the torch en route to the welding nozzle13. The connection fitting 29 is connectable with a conduit (not shown)which perfon'ns the dual purpose of conducting the fluid such as air tothe torch for the operation of the wire-feeding means therein, and alsoincludes a conducting shield of copper, aluminum or other suitable metalwhich forms an electrical conducting path for current supplied to theelectrode wire.

The innermost end of the inlet conduit 28 communicates with a valvecontrol structure (not shown) contained within the end cap 27 of themotor, this valve structure including a projecting control stem 30having its outer end engaged with a valve control lever 31 which extendsalongside the exterior of the handgrip portion where it is easilyengaged by the hand of the welder during the operation of the torch, andcan be easily manipulated to control the speed of the feed mechanismmotor. This lever is hinged at its inner end on a pivot 32, and isadjacently provided with a cam portion 33, the camming edge of which isassociated with an actuating member 34 of an associated microswitch 35having contacts arranged to close an electrical circuit containing theconductors 36 and 37. The closing of this circuit is arranged totakeplace immediately prior to the actuation of the valve control structureto its open position by operation of the valve control lever 31. Thecontacts of the microswitch 35 remain closed during regulatory speedchanges of the feed mechanism on the torch by means of the control lever31.

At the wire-feeding unit 20, the wire is taken from a rotatably mountedreel 38 and passes between a drive roller 39 and an idler roller 40which is arranged to be adjusted by means of a rotatable knob 51 inconventional manner to vary the engagement pressure of the rollers uponthe wire. From the feeding rollers, the wire enters the flexible conduitthrough which it is fed to the welding gun T.

The drive roller 39 is driven through a worm gear and worm transmission41 by means of an electric motor 42 having energizing conductors (notshown) which are carried through a conduit or a cable 43 from a controlbox 44 to which lead the conductors 36 and 37 from the microswitch 35,as well as a connected suitable power supply 45. I

The motor 42 is of the type commonly referred to as a torque motor"which is designed to provide a predetermined maximum torque under stallconditions. The motor has a split main field 46 having a two-partwinding 46a and 46b. As

shown in FIG. 2, the power supply 45 is connected to terminals A and B.The terminal A connects through switch 35 with a common midpoint 47 ofthe windings 46a and 46b, while terminal B is connected through aconductor 48 with the other end of winding 46b. A terminal B connectsthrough a conductor 49 with the other end of winding 46a. For reversedoperationof the "Ol01, the power supply 45 would be connected withterminals A and B.

In order to provide a phase displacement in one of the windings, acapacitor C4 is connected between conductors 48 and 49. This capacitoralso determines the torque rating of the motor.

Accordingto the present invention, it is proposed to change the motortorque from a high maximum stall value when used with relatively largewelding wire to a decreased maximum stall value when used withrelatively smaller welding wire. For this purpose, the change outputtorque characteristics is accomplished by providing a resistor R-l whichis connectable across the capacitor C1 by means of a switch 50. In openposition of the contacts of switch 50, the motor will deliverhigh-torque characteristics, while in the closed position of switch 50the resistor R-l will be connected in circuit with the capacitor 01 andconnect the motor for the low-torque characteristic.

As indicative of specific design characteristics of the presentinvention, it may be stated that the driving motor of the feed roller 21of the welding gun is arranged to advance the wire at a speed ofapproximately 900 inches per minute, and the control by means of lever31 to vary the speed from 50 inches to 600 inches per minute. Similarlythe speed of wire advance at the wirefeeding unit 20 is designed forcomparable continuous feed.

As an example of the type of driving motor which has been utilized atthe wire-feeding unit 20, the following is indicated:

Manufacturer: BODlNE Voltage: 1 15 AC; Single phase; 60 Cycle; l4 WattsR.P.M.-1200 Torque 1.9 inch ounces Capacitor C-] ,l .4 mfd.

Type KC l-26-Al The speed reduction through the worm gear and wormtransmission is 5 to 1.

With the capacitor C4 in the circuit, a torque of approximately 20 inchounces will be delivered from the transmission 41 for use in driving thelarger wires, while with a resistor R-l having a value of substantially3,000 Ohms connected across the capacitor 01, a torque of approximately12 inch ounces will be delivered for use in feeding the smaller sizewires of diameters of the order of .030 to .035 inches.

It will be observed that through the operation of the microswitch 35,the feeding mechanism at the torch and the feeding mechanism at the unit20 will be substantially simultaneously controlled and synchronized.

From the foregoing description and drawings, it will be clearly evidentthat the delineated objects and features of the invention will beaccomplished.

Various modifications may suggest themselves to those skilled in the artwithout departing from the spirit of my invention, and, hence, I do notwish to be restricted to the specific forms shown or uses mentionedexcept to the extentindicated in the appended claims.

I claim:

1. Electrode wire feeding means for welding apparatus, comprising:

a. a source of electrode wire remote from a welding device with whichsaid wire is to be used;

b. means for feeding said electrode wire from said source to a point ofuse at said device including primary wire-feeding means and control atsaid device, and wire-feeding elements at the wire source forwithdrawing the wire from said source and propelling it longitudinallyto said primary wire-feeding means;

c. power means for actuating said elements and constantly delivering adriving torque thereto during movement and nonmovement of said electrodewire, said power means having a predetermined maximum stalled outputtorque limit less than the column strength of said electrode wire; and

d. means for selectively presetting the maximum output torque limit ofsaid power means at different values depending upon the size of saidwire, said values being less than the column strength of the wire,whereby under maximum stall torque conditions wire kinl ting will beprevented between said elements and the primary wirefeeding means.

2. Electrode wire feeding means according to claim 1,

wherein the power means comprises an electric torque motor.

3. Electrode wire-feeding means according to claim 2, wherein the motoris of the split main field type having one field portion containing acapacitor in circuit therewith operative to provide a predeterminedmaximum stall torque output;

and including means for varying the efi'ect of said capacitor to providea maximum stall torque output of a different value.

5. Electrode wire feeding means according to claim 2, wherein the motorhas a two part main field winding, one of said parts having a capacitorin series therewith, whereby to provide a phase shift between the fieldsproduced by the winding parts, and to normally deliver a maximum stalleddriving torque; and including means for connecting a resistor inparallel with said capacitor to decrease the maximum stalled drivingtorque.

6. Electrode wire-feeding means for welding apparatus, comprising:

a. a source of electrode wire remote from a welding device with whichsaid wire is to be used;

b. means for feeding said electrode wire from said source to a point ofuse at said device including feed rollers at the wire source forwithdrawing the wire from said source and propelling it longitudinallytowards said point of use; and

c. electric motor power means for driving said rollers seiective todeliver different values of maximum stall driving torque forces inaccordance with different sizes of the wire, said driving torque forcesbeing less than the column strength of the wire to prevent kinking ofthe wire between said feed rollers and said point of use.

7. Electrode wire-feeding means according to claim 6 wherein the feedingmeans further includes air motor driven feed rollers at said device forpulling said wire.

8. Electrode wire-feeding means according to claim 7, including manuallyoperable control means at said device for simultaneously controllingsaid air motor and said electric motor.

9. Electrode wire-feeding means according to claim 7, wherein theelectric motor power means comprises a torque motor, and including meansselective to change the motor from a high maximum stall torque deliverylimit to a low maximum stall torque delivery limit and vice versa.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,562,577 Dated February 9. 1211 Inventor(s) Milo M. Kenarue It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 3, line 7 8, the word -in-- should appear before "out Column 5,following line 2, insert allowed Claim l, as follo "4. Electrode wirefeeding means according to claim 3, wherein said means for varyim theeffect of said capacitor comprises a resistor connected in a parallelcircu therewith--- Signed and sealed this 13th day of July 1971.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, J! Attesting OfficerComissioner of Patent:

1. Electrode wire feeding means for welding apparatus, comprising: a. asource of electrode wire remote from a welding device with which saidwire is to be used; b. means for feeding said electrode wire from saidsource to a point of use at said device including primary wire-feedingmeans and control at said device, and wire-feeding elements at the wiresource for withdrawing the wire from said source and propelling itlongitudinally to said primary wire-feeding means; c. power means foractuating said elements and constantly delivering a driving torquethereto during movement and nonmovement of said electrode wire, saidpower means having a predetermined maximum stalled output torque limitless than the column strength of said electrode wire; and d. means forselectively presetting the maximum output torque limit of said powermeans at different values depending upon the size of said wire, saidvalues being less than the column strength of the wire, whereby undermaximum stall torque conditions wire kinking will be prevented betweensaid elements and the primary wire-feeding means.
 2. Electrode wirefeeding means according to claim 1, wherein the power means comprises anelectric torque motor.
 3. Electrode wire-feeding means according toclaim 2, wherein the motor is of the split main field type having onefield portion containing a capacitor in circuit therewith operative toprovide a predetermined maximum stall torque output; and including meansfor varying the effect of said capacitor to provide a maximum stalltorque output of a different value.
 5. Electrode wire feeding meansaccording to claim 2, wherein the motor has a two part main fieldwinding, one of said parts having a capacitor in series therewith,whereby to provide a phase shift between the fields produced by thewinding parts, and to normally deliver a maximum stalled driving torque;and including means for connecting a resistor in parallel with saidcapacitor to decrease the maximum stalled driving torque.
 6. Electrodewire-feeding means for welding apparatus, comprising: a. a source ofelectrode wire remote from a welding device with which said wire is tobe used; b. means for feeding said electrode wire from said source to apoint of use at said device including feed rollers at the wire sourcefor withdrawing the wire from said source and propelling itlongitudinally towards said point of use; and c. electric motor powermeans for driving said rollers selective to deliver different values ofmaximum stall driving torque forces in accordance with different sizesof the wire, said driving torque forces being less than the columnstrength of the wire to prevent kinking of the wire between said feedrollers and said point of use.
 7. Electrode wire-feeding means accordingto claim 6, wherein the feeding means further includes air motor drivenfeed rollers at said device for pulling said wire.
 8. Electrodewire-feeding means according to claim 7, including manually operablecontrol means at said device for simultaneously controlling said airmotor and said electric motor.
 9. Electrode wire-feeding means accordingto claim 7, wherein the electric motor power means comprises a torquemotor, and including means selective to change the motor from a highmaximum stall torque delivery limit to a low maximum stall torquedelivery limit and vice versa.